De-virtualize SkCanvas save/restore.

This moves the state management logic into non-virtual SkCanvas methods,
and turns the virtuals into protected notifiers.

R=reed@google.com, robertphillips@google.com

Author: fmalita@chromium.org

Review URL: https://codereview.chromium.org/194713008

git-svn-id: http://skia.googlecode.com/svn/trunk@13776 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/utils/debugger/SkDebugCanvas.cpp b/src/utils/debugger/SkDebugCanvas.cpp
index 08e6d94..279976a 100644
--- a/src/utils/debugger/SkDebugCanvas.cpp
+++ b/src/utils/debugger/SkDebugCanvas.cpp
@@ -530,8 +530,9 @@
     this->addDrawCommand(new SkPopCullCommand());
 }
 
-void SkDebugCanvas::restore() {
-    addDrawCommand(new SkRestoreCommand());
+void SkDebugCanvas::willRestore() {
+    this->addDrawCommand(new SkRestoreCommand());
+    this->INHERITED::willRestore();
 }
 
 bool SkDebugCanvas::rotate(SkScalar degrees) {
@@ -539,15 +540,17 @@
     return true;
 }
 
-int SkDebugCanvas::save(SaveFlags flags) {
-    addDrawCommand(new SkSaveCommand(flags));
-    return true;
+void SkDebugCanvas::willSave(SaveFlags flags) {
+    this->addDrawCommand(new SkSaveCommand(flags));
+    this->INHERITED::willSave(flags);
 }
 
-int SkDebugCanvas::saveLayer(const SkRect* bounds, const SkPaint* paint,
-        SaveFlags flags) {
-    addDrawCommand(new SkSaveLayerCommand(bounds, paint, flags));
-    return true;
+SkCanvas::SaveLayerStrategy SkDebugCanvas::willSaveLayer(const SkRect* bounds, const SkPaint* paint,
+                                                         SaveFlags flags) {
+    this->addDrawCommand(new SkSaveLayerCommand(bounds, paint, flags));
+    this->INHERITED::willSaveLayer(bounds, paint, flags);
+    // No need for a full layer.
+    return kNoLayer_SaveLayerStrategy;
 }
 
 bool SkDebugCanvas::scale(SkScalar sx, SkScalar sy) {